12/16 to 12/17 Godzilla - 1st Call Snow Map

Frank_Wx wrote:

heehaw453 wrote:The 12Z Euro 500mb ULL passes right over our area.  It's not terrible. With the cold air in place that is very good for an 8-12" kind of snowfall.  The > 1' is well west of the area.  In order to get the bigger snow that ULL must be to our east.  I'm just hoping it'd done correcting west at this point.

If only we can get this even 50 miles south. That would also move 700mb/850mb and reduce the impact of dry slotting.

Exactly Frank. It's a whole cascading effects. 50-75 miles is a reasonable adjustment at this range. I still think the block is going to work its magic.

heehaw453 wrote:

Frank_Wx wrote:

heehaw453 wrote:The 12Z Euro 500mb ULL passes right over our area.  It's not terrible. With the cold air in place that is very good for an 8-12" kind of snowfall.  The > 1' is well west of the area.  In order to get the bigger snow that ULL must be to our east.  I'm just hoping it'd done correcting west at this point.

If only we can get this even 50 miles south. That would also move 700mb/850mb and reduce the impact of dry slotting.

Exactly Frank.  It's a whole cascading effects.  50-75 miles is a reasonable adjustment at this range.  I still think the block is going to work its magic.

That airmass outside is already feeling CRISP. Never underestimate a Québécois high.

heehaw453 wrote:The 12Z Euro 500mb ULL passes right over our area.  It's not terrible. With the cold air in place that is very good for an 8-12" kind of snowfall.  The > 1' is well west of the area.  In order to get the bigger snow that ULL must be to our east.  I'm just hoping it'd done correcting west at this point.

You don’t want any closed low- or mid-level lows passing overhead or north/west of you. It maximizes the warm advection aloft and leaves you in “no man’s land” in terms of forcing for ascent. In order to maximize dynamics and cold, the general rule is you want the 700/500mb closed lows to pass between ~100-250 miles to your southeast, depending on the exact evolution. And it is the reasons behind this rule, among other reasons, that you are seeing the models finally adjust northwestward with the best banding on the QPF/snow maps.

The surface high to the north has actually been getting stronger on recent GFS & NAM runs. pic.twitter.com/w637OQVxEI

— Eric Webb (@webberweather) December 15, 2020

With the Euro holding serve it could be a red flag. It could be that the other models over corrected NW. if my assumption is correct you will see the other models shift SE tonight/tomorrow morning. Even if I’m wrong I believe this is far NW the models will go. We’ll see.

Frank_Wx wrote:

The surface high to the north has actually been getting stronger on recent GFS & NAM runs. pic.twitter.com/w637OQVxEI

— Eric Webb (@webberweather) December 15, 2020

This^^^. With a blocking high this strong, any more shifts NW would be shocking to me. Either it’s going against the law of physics or it’s just incredibly bad luck.

Sounds like there may once again be some disappointed folks after this, especially seeing as the expectations are so very high

Yes I agree how can a pretty weak system push through a even stronger HP, that doesnt make any logical sense. Only 2020, maybe the models have COVID lol (no jokes aside that covid isn't serious)

nutleyblizzard wrote:

Frank_Wx wrote:

The surface high to the north has actually been getting stronger on recent GFS & NAM runs. pic.twitter.com/w637OQVxEI

— Eric Webb (@webberweather) December 15, 2020

This^^^. With a blocking high this strong, any more shifts NW would be shocking to me. Either it’s going against the law of physics or it’s just incredibly bad luck.

The problem I think you’re having is that you are conflating the surface high pressure with the steering mechanism of the low’s entire atmospheric column, and it’s not the case. Yes, the surface high has trended stronger, but it’s also slipping further east versus previous runs thanks to the added space created by the blocking “50/50” low slipping further east. Additionally, this allows heights to raise more out ahead of the mid-level lows as the compression from the blocking is less thanks to the above, and warm advection on the return flow of the high is enhanced. As a result, this helps sharpen the trough associated with our storm at all levels and back the flow to more southerly as the troughs tilt negative and close off. This allows for enhanced warm advection and greater latitude gains of the low through the entire atmospheric column.

Frank_Wx wrote:

This trend in the shortwave is likely due to it finally being adequately sampled by radiosondes over N America this morning. Just goes to show how critical in-situ observations are to operational weather forecasts! https://t.co/6TTEvnDbc0 pic.twitter.com/mVVM7Dqizb

— Eric Webb (@webberweather) December 15, 2020

I think the quote around how critical in-situ observations are to operational weather forecasts is great and true. I love this forum and the well in advance information I get on an impending storm. But I've seen some criticisms around local Mets posting initially very low snowfall forecasts knowing what we've seen in model runs well in advance of a storm - even why the NWS doesn't post winter weather headlines outside of 48 hours. While these outlets must make people aware that something may be imminent, they have a huge audience and can't go ringing the alarms until there is as much confidence as possible. I think they're all still licking the wounds from Juno back in the day lol.

Maybe, but the real issue is the track of the mid level lows. The HP is going to help some, but its main purpose is to supply cold air and prevent a surface low from cutting too far west.

To get the mid level lows a little more south, you would need less interaction between the broad level H5 trough and northern s/w energy. Now that all of the H5 energy is being properly sampled by satellite, we're seeing model trend NW.

The only thing that matters now is how high heights get along the east coast. This map shows the 48 hour trend at H5. Blue = deeper/stronger trough, red over the coast means more amplified ridging/higher heights which correlates to a more NW track of the surface low that not even an HP can fix.

rb924119 wrote:

heehaw453 wrote:The 12Z Euro 500mb ULL passes right over our area.  It's not terrible. With the cold air in place that is very good for an 8-12" kind of snowfall.  The > 1' is well west of the area.  In order to get the bigger snow that ULL must be to our east.  I'm just hoping it'd done correcting west at this point.

You don’t want any closed low- or mid-level lows passing overhead or north/west of you. It maximizes the warm advection aloft and leaves you in “no man’s land” in terms of forcing for ascent. In order to maximize dynamics and cold, the general rule is you want the 700/500mb closed lows to pass between ~100-250 miles to your southeast, depending on the exact evolution. And it is the reasons behind this rule, among other reasons, that you are seeing the models finally adjust northwestward with the best banding on the QPF/snow maps.

Absolutely agree with you. I believe the Euro snow output based on the storm's trajectory was very generous. I think you'd have problems of taint and dry slotting in our area with that track.

crippo84 wrote:

Frank_Wx wrote:

This trend in the shortwave is likely due to it finally being adequately sampled by radiosondes over N America this morning. Just goes to show how critical in-situ observations are to operational weather forecasts! https://t.co/6TTEvnDbc0 pic.twitter.com/mVVM7Dqizb

— Eric Webb (@webberweather) December 15, 2020

I think the quote around how critical in-situ observations are to operational weather forecasts is great and true. I love this forum and the well in advance information I get on an impending storm. But I've seen some criticisms around local Mets posting initially very low snowfall forecasts knowing what we've seen in model runs well in advance of a storm - even why the NWS doesn't post winter weather headlines outside of 48 hours. While these outlets must make people aware that something may be imminent, they have a huge audience and can't go ringing the alarms until there is as much confidence as possible. I think they're all still licking the wounds from Juno back in the day lol.

Agree, but NWS Mt. Holly issued an 18-24" forecast yesterday for a huge portion of the area. I don't think they updated it yet either.

Its one thing for me to do that (only have like 10 followers, right???), but those Meteorologists must have believed the S-SE track too!!

crippo84 wrote:

Frank_Wx wrote:

This trend in the shortwave is likely due to it finally being adequately sampled by radiosondes over N America this morning. Just goes to show how critical in-situ observations are to operational weather forecasts! https://t.co/6TTEvnDbc0 pic.twitter.com/mVVM7Dqizb

— Eric Webb (@webberweather) December 15, 2020

I think the quote around how critical in-situ observations are to operational weather forecasts is great and true. I love this forum and the well in advance information I get on an impending storm. But I've seen some criticisms around local Mets posting initially very low snowfall forecasts knowing what we've seen in model runs well in advance of a storm - even why the NWS doesn't post winter weather headlines outside of 48 hours. While these outlets must make people aware that something may be imminent, they have a huge audience and can't go ringing the alarms until there is as much confidence as possible. I think they're all still licking the wounds from Juno back in the day lol.

This is a great post! It’s relatively easy to sit at your computer desk and play Monday morning quarterback, and as mets we do take a lot of criticism. We often times have to walk a very fine line of disseminating the information, expressing the uncertainties, and not hyping things. The problem is fewer and fewer mainstream mets DON’T try to not sensationalize things for reasons I will not discuss here, and the most important thing they don’t do is take responsibility for their forecasts. And this is exactly what I brought up to Frank earlier, and why I told him he shouldn’t feel like people are seeing his updates in a “political” light. He presented his information, provided his interpretation, explained what factors he felt might change his forecast. I think he balanced the task well there, in stead of just saying “Well, the models changed”. Yes. We know they changed, we have two eyes, we can see that, but HOW did that change your forecast? Frank explained that, most other mainstream mets don’t. That drives me nuts. People would be much more forgiving if they took responsibility and explained some of their reasoning (briefly/simply, obviously), instead of just passing blame on the models and making it look like hype. So in that respect, I feel that the criticism is warranted.

If someone has time, post the current look of the 500mb trough using the mesoscale NWS site. Compare the actual observation to a couple of models (GFS/NAM to start?)

Frank_Wx wrote:

crippo84 wrote:

Frank_Wx wrote:

This trend in the shortwave is likely due to it finally being adequately sampled by radiosondes over N America this morning. Just goes to show how critical in-situ observations are to operational weather forecasts! https://t.co/6TTEvnDbc0 pic.twitter.com/mVVM7Dqizb

— Eric Webb (@webberweather) December 15, 2020

I think the quote around how critical in-situ observations are to operational weather forecasts is great and true. I love this forum and the well in advance information I get on an impending storm. But I've seen some criticisms around local Mets posting initially very low snowfall forecasts knowing what we've seen in model runs well in advance of a storm - even why the NWS doesn't post winter weather headlines outside of 48 hours. While these outlets must make people aware that something may be imminent, they have a huge audience and can't go ringing the alarms until there is as much confidence as possible. I think they're all still licking the wounds from Juno back in the day lol.

Agree, but NWS Mt. Holly issued an 18-24" forecast yesterday for a huge portion of the area. I don't think they updated it yet either.

Its one thing for me to do that (only have like 10 followers, right???), but those Meteorologists must have believed the S-SE track too!!

Haha looking at the active members list you're doing a hell of a lot better than 10 followers. I've been following your forecasts since the ABC forum days. I have nothing but respect and appreciation for all you contribute - I go nowhere else when we have a winter storm approaching. Keep up the insanely great work guys!

So If I am reading all the analysis from our top forcasters here is that this is no longer a big storm for down here? And that its NW is correct and could go even more NW which would give us like nothing or just rain? I have so many people asking me and I got no clue what to tell them cuz the pro mets are still calling a big storm and my news pop ups are flooded with huge storm for NYC.

jmanley32 wrote:So If I am reading all the analysis from our top forcasters here is that this is no longer a big storm for down here? And that its NW is correct and could go even more NW which would give us like nothing or just rain? I have so many people asking me and I got no clue what to tell them cuz the pro mets are still calling a big storm and my news pop ups are flooded with huge storm for NYC.

Tell them 0 to 18"

Frank_Wx wrote:

jmanley32 wrote:So If I am reading all the analysis from our top forcasters here is that this is no longer a big storm for down here? And that its NW is correct and could go even more NW which would give us like nothing or just rain? I have so many people asking me and I got no clue what to tell them cuz the pro mets are still calling a big storm and my news pop ups are flooded with huge storm for NYC.

Tell them 0 to 18"

LMAO, Yeah that will get me nowhere and a promet really nowhere. I actually said a smal lto nothing sotrm, a medium storm or a big storm, very concise I know. I hate this 24 hr lead up waiting game sigh. Especiually when it doesnt look so hot but I am go stick it through till its showing snow outside or not.

TWC just adjusted snow totals for my area in CNJ from 12-18 down to 7-12. Still a very nice storm but the move N&W seems to be happening. Time will tell...

Jman some of our members are going to get a big storm just don't know who yet, it could be up in Albany with Math! Even me up in Ulster I was thinking this would be south of me now I could be in a great spot or the bigger snows go to my north and west time will tell!

Frank_Wx wrote:

jmanley32 wrote:So If I am reading all the analysis from our top forcasters here is that this is no longer a big storm for down here? And that its NW is correct and could go even more NW which would give us like nothing or just rain? I have so many people asking me and I got no clue what to tell them cuz the pro mets are still calling a big storm and my news pop ups are flooded with huge storm for NYC.

Tell them 0 to 18"

Now THIS is a “never wrong” answer

So I’m guessing for my area in the Bronx it’s going from snow to sleet to crap I just told everyone we’re getting a lot of snow

Reading the Mt. Holly discussion from mid-morning they seem well aware of the NW trend and the increasing risk of WAA infiltrating the storm and causing a mixing of precipitation. But it seems despite that they're still confident in this producing a foot or more of snow north and west of the I-95 corridor and in the I-95 corridor still believe several inches are likely even with mixing. So either they believe we've seen as much as we're going to see of a NW drift or they're just slow to back off the WSW they issued early this morning.
I always feel a lot of the angst here is based off of the expectations game too. I've watched these model runs and even on some of the ones that seem disappointing, I'm still getting about 10" of snow as are many others. If a week ago you told me you'll get 6-10" of snow from a storm next Wednesday I would have said, "where do I sign." But when you start thinking in terms of 18-24" suddenly when the models correct lower to the high-singled digits, it seems like the sky is falling (pardon the pun).
Now, if this goes predominately rain, or I get dry slotted and I end up with 1-3" (like that one God awful model run earlier today that CP so appropriately commented on), yeah, I'd be VERY disappointed. But I'm hard pressed to say that if I end up even in a 4-8" range that I shouldn't be happy with that.
So I've yet to see many model runs that still wouldn't produce a significant snow event for many on this board, even if it ends up not being a mega-storm.

TWC, not that i really follow them or even trust them have not changed their forecast here which doesnt make much sense if they are lowering NJ totals. Of course upton is the last to do things but I do not know if TWC goes by NWS.

frank 638 wrote:So I’m guessing for my area in the Bronx it’s going from snow to sleet to crap I just told everyone we’re getting a lot of snow

Ohhhhh you go get the wooden spoon lol or the slip.